51
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Willott JD, Murdoch TJ, Humphreys BA, Edmondson S, Webber GB, Wanless EJ. Critical salt effects in the swelling behavior of a weak polybasic brush. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:1827-36. [PMID: 24476028 DOI: 10.1021/la4047275] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
The swelling behavior of poly(2-(diethylamino)ethyl methacrylate) (PDEA) brushes in response to changes in solution pH and ionic strength has been investigated. The brushes were synthesized by ARGET ATRP methodology at the silica-aqueous solution interface via two different surface-bound initiator approaches: electrostatically adsorbed cationic macroinitiator and covalently anchored silane-based ATRP initiator moieties. The pH-response of these brushes is studied as a function of the solvated brush thickness in a constant flow regime that elucidates the intrinsic behavior of polymer brushes. In situ ellipsometry equilibrium measurements show the pH-induced brush swelling and collapse transitions are hysteretic in nature. Furthermore, high temporal resolution kinetic studies demonstrate that protonation and solvent ingress during swelling occur much faster than the brush charge neutralization and solvent expulsion during collapse. This hysteresis is attributed to the formation of a dense outer region or skin during collapse that retards solvent egress. Moreover, at a constant pH below its pKa, the PDEA brush exhibited a critical conformational change in the range 0.5-1 mM electrolyte, a range much narrower than predicted by the theory of the osmotic brush regime. This behavior is attributed to the hydrophobicity of the collapsed brush. The swelling and collapse kinetics for this salt-induced transition are nearly identical. This is in contrast to the asymmetry in the rate of the pH-induced response, suggesting an alternative mechanism for the two processes dependent on the nature of the environmental trigger.
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Affiliation(s)
- Joshua D Willott
- Priority Research Centre for Advanced Particle Processing and Transport, University of Newcastle , Callaghan, NSW 2308, Australia
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52
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Lorbeer L, Alaghemandi M, Spohr E. Molecular dynamics studies of poly(N-isopropylacrylamide) endgrafted on the surfaces of model slab pores. J Mol Liq 2014. [DOI: 10.1016/j.molliq.2013.05.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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53
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Shi XJ, Chen GJ, Wang YW, Yuan L, Zhang Q, Haddleton DM, Chen H. Control the wettability of poly(n-isopropylacrylamide-co-1-adamantan-1-ylmethyl acrylate) modified surfaces: the more Ada, the bigger impact? LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:14188-14195. [PMID: 24152189 DOI: 10.1021/la4037748] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Surface-initiated SET-LRP was used to synthesize polymer brush containing N-isopropylacrylamide and adamantyl acrylate using Cu(I)Cl/Me6-TREN as precursor catalyst and isopropanol/H2O as solvent. Different reaction conditions were explored to investigate the influence of different parameters (reaction time, catalyst concentration, monomer concentration) on the polymerization. Copolymers with variable 1-adamantan-1-ylmethyl acrylate (Ada) content and comparable thickness were synthesized onto silicon surfaces. Furthermore, the hydrophilic and bioactive molecule β-cyclodextrin-(mannose)7 (CDm) was synthesized and complexed with adamantane via host-guest interaction. The effect of adamantane alone and the effect of CDm together with adamantane on the wettability and thermoresponsive property of surface were investigated in detail. Experimental and molecular structure analysis showed that Ada at certain content together with CDm has the greatest impact on surface wettability. When Ada content was high (20%), copolymer-CDm surfaces showed almost no CDm complexed with Ada as the result of steric hindrance.
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Affiliation(s)
- Xiu-Juan Shi
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University , Suzhou 215123, P. R. China
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54
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Cui Q, Shen G, Wu F, Wang E. Two-step phase transition via in situ hydrolysis of thermosensitive polymeric micelles with acid-labile core. Colloid Polym Sci 2013. [DOI: 10.1007/s00396-013-2989-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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55
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Gong K, Marshall BD, Chapman WG. Modeling lower critical solution temperature behavior of associating polymer brushes with classical density functional theory. J Chem Phys 2013; 139:094904. [DOI: 10.1063/1.4819957] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
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56
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Chemical and morphological characterization of sulfonated polystyrene brushes in different environments. Eur Polym J 2013. [DOI: 10.1016/j.eurpolymj.2013.04.025] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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57
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Choi BC, Choi S, Leckband DE. Poly(N-isopropyl acrylamide) brush topography: dependence on grafting conditions and temperature. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:5841-5850. [PMID: 23600842 DOI: 10.1021/la400066d] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The topography of poly (N-isopropyl acrylamide) brushes end-grafted from initiator-terminated monolayers was imaged by atomic force microscopy, as a function of the area per chain and of solvent quality. Measurements were done in air and in water, below and above the lower critical solution temperature. At low grafting densities and molecular weights, area-averaged ellipsometry measurements did not detect changes in the volume of water-swollen, end-grafted polymer films above the lower critical solution temperature. However, atomic force microscopy images revealed surface features that suggest the formation of lateral aggregates or "octopus micelles". At high grafting densities and molecular weights, the films collapsed uniformly, as detected by both AFM imaging and ellipsometry. These findings reconcile in part prior results suggesting that some poly(N-isopropyl acrylamide) chains do not collapse in poor solvent, and they also reveal more complex collapse behavior above the lower critical solution temperature than is commonly assumed. This behavior would influence the ability to tune the functional properties of poly(N-isopropyl acrylamide) coatings.
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Affiliation(s)
- B-C Choi
- Department of Chemical and Biomolecular Engineering, University of Illinois, Urbana, Illinois 61801, United States
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58
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Wang H, Wang Y, Yuan L, Wang L, Yang W, Wu Z, Li D, Chen H. Thermally responsive silicon nanowire arrays for native/denatured-protein separation. NANOTECHNOLOGY 2013; 24:105101. [PMID: 23416357 DOI: 10.1088/0957-4484/24/10/105101] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We present our findings of the selective adsorption of native and denatured proteins onto thermally responsive, native-protein resistant poly(N-isopropylacrylamide) (PNIPAAm) decorated silicon nanowire arrays (SiNWAs). The PNIPAAm-SiNWAs surface, which shows very low levels of native-protein adsorption, favors the adsorption of denatured proteins. The amount of denatured-protein adsorption is higher at temperatures above the lower critical solution temperature (LCST) of PNIPAAm. Temperature cycling surrounding the LCST, which ensures against thermal denaturation of native proteins, further increases the amount of denatured-protein adsorption. Moreover, the PNIPAAm-SiNWAs surface is able to selectively adsorb denatured protein even from mixtures of different protein species; meanwhile, the amount of native proteins in solution is kept nearly at its original level. It is believed that these results will not only enrich current understanding of protein interactions with PNIPAAm-modified SiNWAs surfaces, but may also stimulate applications of PNIPAAm-SiNWAs surfaces for native/denatured protein separation.
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Affiliation(s)
- Hongwei Wang
- Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application, Department of Polymer Science and Engineering, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, 199 Ren'ai Road, Suzhou, 215123, People's Republic of China
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59
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Alaghemandi M, Spohr E. A molecular dynamics study of poly(N-isopropylacrylamide) endgrafted on a model cylindrical pore surface. RSC Adv 2013. [DOI: 10.1039/c3ra22266g] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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60
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Seo JH, Yui N. The effect of molecular mobility of supramolecular polymer surfaces on fibroblast adhesion. Biomaterials 2013; 34:55-63. [DOI: 10.1016/j.biomaterials.2012.09.063] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2012] [Accepted: 09/26/2012] [Indexed: 10/27/2022]
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61
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Gao G, Dallmeyer JI, Kadla JF. Synthesis of Lignin Nanofibers with Ionic-Responsive Shells: Water-Expandable Lignin-Based Nanofibrous Mats. Biomacromolecules 2012; 13:3602-10. [DOI: 10.1021/bm301039f] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Guangzheng Gao
- Advanced
Biomaterials Chemistry Lab, Faculty
of Forestry, The University of British Columbia, Vancouver, BC, Canada V6T 1Z4
| | - James Ian Dallmeyer
- Advanced
Biomaterials Chemistry Lab, Faculty
of Forestry, The University of British Columbia, Vancouver, BC, Canada V6T 1Z4
| | - John F. Kadla
- Advanced
Biomaterials Chemistry Lab, Faculty
of Forestry, The University of British Columbia, Vancouver, BC, Canada V6T 1Z4
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62
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Kooij ES, Sui X, Hempenius MA, Zandvliet HJW, Vancso GJ. Probing the Thermal Collapse of Poly(N-isopropylacrylamide) Grafts by Quantitative in Situ Ellipsometry. J Phys Chem B 2012; 116:9261-8. [DOI: 10.1021/jp304364m] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- E. Stefan Kooij
- Physics of Interfaces and Nanomaterials,
MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500AE Enschede, The Netherlands
| | - Xiaofeng Sui
- Materials Science and Technology
of Polymers, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500AE Enschede, The Netherlands
| | - Mark A. Hempenius
- Materials Science and Technology
of Polymers, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500AE Enschede, The Netherlands
| | - Harold J. W. Zandvliet
- Physics of Interfaces and Nanomaterials,
MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500AE Enschede, The Netherlands
| | - G. Julius Vancso
- Materials Science and Technology
of Polymers, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500AE Enschede, The Netherlands
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63
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Azzaroni O. Polymer brushes here, there, and everywhere: Recent advances in their practical applications and emerging opportunities in multiple research fields. ACTA ACUST UNITED AC 2012. [DOI: 10.1002/pola.26119] [Citation(s) in RCA: 306] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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64
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Olivier A, Meyer F, Raquez JM, Damman P, Dubois P. Surface-initiated controlled polymerization as a convenient method for designing functional polymer brushes: From self-assembled monolayers to patterned surfaces. Prog Polym Sci 2012. [DOI: 10.1016/j.progpolymsci.2011.06.002] [Citation(s) in RCA: 208] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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65
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Elliott LCC, Barhoum M, Harris JM, Bohn PW. Single molecule tracking studies of lower critical solution temperature transition behavior in poly(N-isopropylacrylamide). LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:11037-11043. [PMID: 21770465 DOI: 10.1021/la201753v] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Spatial and temporal heterogeneities in expanded and collapsed surface bound poly(N-isopropylacrylamide), pNIPAAm, films are studied by single molecule tracking (SMT) experiments. Tracking data are analyzed using both radius of gyration (R(g)) evolution and confinement level calculations to elucidate the range of behaviors displayed by single Rhodamine6G (R6G) molecules. Confined diffusion that is dictated by the free volume within surface tethered chains is observed with considerable dispersion among individual R6G molecules. Thus, the distribution of probe behavior reflects nanometer-scale information about the behavior of the probe-polymer system at temperatures above (T > T(LCST)) and below (T < T(LCST)) the lower critical solution temperature (LCST). In this context, confinement-level analysis and R(g) evolution both show a larger degree of confinement of the probe in pNIPAAm at T > T(LCST). Temperature-dependent changes in confinement are evidenced at T > T(LCST) by a higher percentage of confined steps, longer periods of confined events, and smaller area of confined zones, as well as a shift in the overall distribution of R(g) evolution paths and final R(g) distributions.
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Affiliation(s)
- Lindsay C C Elliott
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, Illinois 61801, USA
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66
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Zoppe JO, Österberg M, Venditti RA, Laine J, Rojas OJ. Surface Interaction Forces of Cellulose Nanocrystals Grafted with Thermoresponsive Polymer Brushes. Biomacromolecules 2011; 12:2788-96. [DOI: 10.1021/bm200551p] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Justin O. Zoppe
- Department of Forest Biomaterials, North Carolina State University, Campus Box 8005, Raleigh, North Carolina, United States
| | - Monika Österberg
- Department of Forest Products Technology, School of Chemical Technology, Aalto University, P.O. Box 16300, Aalto FIN-00076, Finland
| | - Richard A. Venditti
- Department of Forest Biomaterials, North Carolina State University, Campus Box 8005, Raleigh, North Carolina, United States
| | - Janne Laine
- Department of Forest Products Technology, School of Chemical Technology, Aalto University, P.O. Box 16300, Aalto FIN-00076, Finland
| | - Orlando J. Rojas
- Department of Forest Biomaterials, North Carolina State University, Campus Box 8005, Raleigh, North Carolina, United States
- Department of Forest Products Technology, School of Chemical Technology, Aalto University, P.O. Box 16300, Aalto FIN-00076, Finland
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67
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Sui X, Chen Q, Hempenius MA, Vancso GJ. Probing the collapse dynamics of poly(N-isopropylacrylamide) brushes by AFM: effects of co-nonsolvency and grafting densities. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2011; 7:1440-7. [PMID: 21506265 DOI: 10.1002/smll.201002229] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2010] [Revised: 01/17/2011] [Indexed: 05/05/2023]
Abstract
Collapse of poly(N-isopropylacrylamide) (PNIPAM) brushes in the mixed solvent system (water/methanol 50% v/v) is studied by in-situ atomic-force microscopy (AFM). PNIPAM brushes with three different grafting densities and similar chain lengths are synthesized via surface-initiated atom-transfer radical polymerization. By changing the solvent from water to a water/methanol (50% v/v) mixture, the polymer brushes switch from a swollen to collapsed state. AFM force measurements using a silica colloidal probe attached to the tip are employed to obtain the Young's moduli of the polymer brushes in different solvation states. The collapse dynamics of the brush is followed by monitoring the pull-off force (adherence) in situ. The modulus of the swollen high-density polymer brush is four times lower than that of the same brush in the collapsed state. It is shown that in the case of the high-density polymer brush with a thickness (t(in water) ) of 900 nm, the collapse takes place in a time scale of ~25 s, whereas the collapse occurs faster for the medium-density brush (t(in water) = 630 nm) and much more rapidly for the low-density brush (t(in water) = 80 nm). This difference in the response kinetics is primarily ascribed to the time needed for solvent exchange in the polymer brushes.
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Affiliation(s)
- Xiaofeng Sui
- Department of Materials Science and Technology of Polymers, University of Twente, MESA+ Institute for Nanotechnology, Enschede, The Netherlands
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68
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Herzberg M, Sweity A, Brami M, Kaufman Y, Freger V, Oron G, Belfer S, Kasher R. Surface Properties and Reduced Biofouling of Graft-Copolymers That Possess Oppositely Charged Groups. Biomacromolecules 2011; 12:1169-77. [DOI: 10.1021/bm101470y] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Moshe Herzberg
- Department of Desalination and Water Treatment, Zuckerberg Institute for Water Research, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus 84990, Israel
| | - Amer Sweity
- Department of Desalination and Water Treatment, Zuckerberg Institute for Water Research, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus 84990, Israel
| | - Matan Brami
- Department of Desalination and Water Treatment, Zuckerberg Institute for Water Research, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus 84990, Israel
| | - Yair Kaufman
- Department of Desalination and Water Treatment, Zuckerberg Institute for Water Research, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus 84990, Israel
| | - Viatcheslav Freger
- Department of Desalination and Water Treatment, Zuckerberg Institute for Water Research, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus 84990, Israel
| | - Gideon Oron
- Department of Desalination and Water Treatment, Zuckerberg Institute for Water Research, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus 84990, Israel
| | - Sophia Belfer
- Department of Desalination and Water Treatment, Zuckerberg Institute for Water Research, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus 84990, Israel
| | - Roni Kasher
- Department of Desalination and Water Treatment, Zuckerberg Institute for Water Research, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus 84990, Israel
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69
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Möller M, Hentschel C, Chi L, Studer A. Aggregation behaviour of peptide-polymer conjugates containing linear peptide backbones and multiple polymer side chains prepared by nitroxide-mediated radical polymerization. Org Biomol Chem 2011; 9:2403-12. [PMID: 21321771 DOI: 10.1039/c0ob01047b] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
A series of peptides with an alternating sequence of alkoxyamine conjugated lysine and glycine residues were synthesized by classical solution phase peptide coupling. The resulting peptides containing up to eight alkoxyamine moieties were used as initiators in nitroxide-mediated polymerization (NMP) to obtain peptide-polymer conjugates with well defined linear peptide backbones and a defined number of polymeric side chains. Polymerization of styrene and N-isopropylacrylamide (NIPAM) occurred in a highly controlled fashion. Molecular weight and polydispersity index (PDI) were determined by gel permeation chromatography (GPC). Aggregation behaviour of these hybrid materials was investigated by dynamic light scattering (DLS) and atomic force microscopy (AFM). Depending on composition, number and length of the polymer side chains, the conjugates aggregate to different topologies. Whereas peptide-polystyrene conjugates may aggregate to so called honeycomb structures, peptide-poly-N-isopropylacrylamide conjugates show differentiated aggregation behaviour.
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Affiliation(s)
- Michael Möller
- Organisch-Chemisches Institut and NRW Graduate School of Chemistry, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149, Münster, Germany
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70
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Sui X, Di Luca A, Gunnewiek MK, Kooij ES, van Blitterswijk CA, Moroni L, Hempenius MA, Vancso GJ. Stability and Cell Adhesion Properties of Poly(N-isopropylacrylamide) Brushes with Variable Grafting Densities. Aust J Chem 2011. [DOI: 10.1071/ch11168] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Poly(N-isopropylacrylamide) brushes with three different grafting densities were synthesized via surface-initiated atom-transfer radical polymerization on glass or on silicon substrates. The substrates were modified with monochlorosilane-based or trimethoxysilane-based atom-transfer radical polymerization initiators. Atomic force microscopy images showed detachment of brushes from the monochlorosilane-based system under cell culture conditions. In situ ellipsometry demonstrated the reversible swelling and collapse of the brushes as the temperature was varied across the lower critical solution temperature of poly(N-isopropylacrylamide) in pure water. The polymer brushes were evaluated as supporting substrates for MC-3T3 cell cultures. At 37°C (T>lower critical solution temperature), the seeded cells adhered, spread, and proliferated, whereas at 25°C (T<lower critical solution temperature), the cells detached from the surface. The low-density polymer brush showed the highest cell adhesion, featuring adhering cells with an elongated morphology.
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